Method and apparatus for vehicle stability enhancement system

• US 20040098184A1
• Filed: 11/18/2002
• Published: 05/20/2004
• Est. Priority Date: 11/18/2002
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Ghoneim, Youssef Ahmed, Jenny, Thomas, Bielaczek, Christian
• Granted Patent: US 6,813,552 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• CPC Class Codes: B60T 8/17555 specially adapted for enhancing driver or passenger comfort, e.g. soft intervention or pre-actuation strategies

Abstract

A vehicle stability enhancement (VSE) system for a vehicle having at least one vehicle subsystem includes; at least one sensor for sensing at least one vehicle parameter, at least one vehicle control system for adjusting the at least one vehicle subsystem, a driving mode switch for selecting at least one driving mode, at least one memory comprising at least one set of gain factors, and a controller responsive to the at least one sensor, the driving mode switch, and the at least one set of gain factors for controlling the at least one vehicle control system.

Claims

1. A vehicle stability enhancement system for a vehicle having at least one vehicle subsystem, comprising:

at least one sensor for sensing at least one vehicle parameter;

at least one vehicle control system for adjusting the at least one vehicle subsystem;

a driving mode switch for selecting at least one driving mode;

at least one memory comprising at least one set of gain factors; and

a controller responsive to said at least one sensor, said driving mode switch, and said at least one set of gain factors for controlling said at least one vehicle control system.

2. The vehicle stability enhancement system of claim 1, wherein said at least one sensor comprises:

a yaw sensor for sensing the vehicle yaw rate;

at least one velocity sensor for sensing the velocity of the vehicle;

a lateral acceleration sensor for sensing the vehicle lateral acceleration;

a steering angle sensor for sensing the vehicle steering angle; and

a pressure sensor for sensing the brake fluid pressure;

wherein

signals from said sensors are received at said controller.

3. The vehicle stability enhancement system of claim 1, wherein said at least one vehicle control system comprises:

a steering mechanism control system for adjusting a steering mechanism; and

a braking mechanism control system for adjusting a braking mechanism.

4. The vehicle stability enhancement system of claim 1, wherein said at least one memory further comprises:

at least one look-up table comprising said at least one set of gain factors.

5. The vehicle stability enhancement system of claim 1, wherein said at least one set of gain factors comprises:

a yaw rate error threshold gain factor; and

a brake pressure apply rate gain factor.

6. The vehicle stability enhancement system of claim 1, wherein said at least one memory further comprises:

a VSE flag register settable to OFF and ON for indicating the state of a VSE system.

7. The vehicle stability enhancement system of claim 6, wherein said at least one memory further comprises:

a vehicle yaw rate error register for storing a vehicle yaw rate error value; and

a vehicle yaw rate error threshold register for storing a vehicle yaw rate error threshold value;

wherein

said VSE flag register is set to ON in response to the absolute value of said vehicle yaw rate error exceeding said vehicle yaw rate error threshold value.

8. The vehicle stability enhancement system of claim 1, wherein said at least one memory further comprises:

at least one vehicle parameter register for storing at least one vehicle parameter value in response to said at least one sensor;

at least one vehicle parameter threshold register for storing at least one vehicle parameter threshold value; and

an OSUS index register settable to at least one value in response to the absolute value of said at least one vehicle parameter exceeding said at least one vehicle parameter threshold value.

9. The vehicle stability enhancement system of claim 8, wherein:

said at least one set of gain factors have values responsive to said at least one value of said OSUS index.

10. The vehicle stability enhancement system of claim 1, wherein said at least one memory further comprises:

an SFlag register settable to OFF and ON for indicating the state of a high friction surface flag;

an LFlag register settable to OFF and ON for indicating the state of a limit stability flag; and

an OSUS index register settable to at least one value in response to said SFlag and said LFlag register settings.

11. A method for actively controlling a vehicle stability enhancement system, comprising:

sensing at least one vehicle parameter;

calculating a yaw rate error index in response to the at least one vehicle parameter;

calculating the state of at least one control flag in response to the at least one vehicle parameter;

determining the state of a driving mode in response to a driving mode request;

determining the state of the at least one control flag in response to the state of the driving mode; and

determining at least one control gain factor in response to the state of the at least one control flag and the yaw rate error index.

12. The method of controlling set forth in claim 11, wherein said sensing at least one vehicle parameter further comprises:

sensing the vehicle yaw rate;

sensing the vehicle velocity;

sensing the vehicle lateral acceleration;

sensing the brake fluid pressure; and

sensing the vehicle steering angle.

13. The method of controlling set forth in claim 11, wherein said calculating a yaw rate error index further comprises:

calculating a yaw rate error index in response to the ratio of vehicle yaw rate error to vehicle yaw rate error threshold.

14. The method of controlling set forth in claim 11, wherein said calculating the state of at least one control flag further comprises:

calculating the state of an SFlag register for indicating the state of a high friction surface flag; and

calculating the state of an LFlag register for indicating the state of a limit stability flag.

15. The method of controlling set forth in claim 11, wherein said determining the state of a driving mode further comprises:

determining whether the driving mode is Normal or Sporty.

16. The method of controlling set forth in claim 14, wherein said calculating the state of an SFlag register comprises:

calculating the SFlag to an ON state.

17. The method of controlling set forth in claim 14, wherein said calculating the state of an LFlag register comprises:

calculating the LFlag to an OFF state.

18. The method of controlling set forth in claim 11, further comprising:

calculating the state of a VSE flag for indicating the state of a vehicle stability enhancement system.

19. The method of controlling set forth in claim 18, wherein said calculating the state of a VSE flag further comprises:

calculating the state of the VSE flag to ON in response to the absolute value of the vehicle yaw rate error exceeding the vehicle yaw rate error threshold value.

20. The method of controlling set forth in claim 11, wherein said determining at least one control gain factor further comprises:

determining a yaw rate error threshold gain factor; and

determining a brake pressure apply rate gain factor.